Subminiature thermal circuit breakers are widely used in applications in which spatial limitations are of particular importance, such as in aircraft. Such devices employ, for example, a thermostatic current carrying member that upon a selected overload condition causes a latching mechanism to unlatch and open a circuit path connected to the breaker by the movement of at least one movable electrical contact from a mating stationary electrical contact.
In recent years there has been a trend to add other functions to such circuit breakers, for example, providing various auxiliary circuits including arc fault protection. Among the challenges that must be dealt with in providing such enhancements is a space limitation for such circuit breakers. For many applications the space available for an individual circuit breaker cannot be significantly increased, even though new functions are added, due to the existing layout of the control panel in which such circuit breakers are mounted.
Typically, subminiature circuit breakers presently in use have first and second line terminals mounted in the circuit breaker housing that extend through respective openings in a selected wall, such as a bottom wall, for secure attachment to a circuit path, as by threaded interconnection therewith as shown, for example, in U.S. Pat. No. 3,361,882, assigned to the assignee of the present invention, the subject matter of which is incorporated herein by this reference. When auxiliary circuits are provided, it is known to provide a socket having a metal member for electrical connection and another metal member formed with spring fingers for engaging a shouldered connector pin, such as military specification connector (M39029), to retain the connector pin in a socket. Such use involves a compromise between using a spring member having desired low force to reduce stress for optimum long life and the need for making the fingers relatively rigid to resist buckling of the fingers when extraction of the connector pin is attempted with the result that retentive capability of the socket is sacrificed.